Can't remove dependency without breaking git

[Mattsi-Jansky]

We want to remove the pre-git dependency from one of our repos that's used semi-regularly across two big teams. The problem we've found is that the pre-commit hooks have already been installed in the repo checkouts of anyone that has built it before. Thus, if we remove the dependency all of their git actions will fail because ./node_modules/.bin/commit-msg is missing.

This would be really simple to fix by wrapping ./node_modules/.bin/commit-msg in a if clause, and make removing this dependency much easier.